<h2>DESCRIPTION</h2>

<em>i.albedo</em> calculates the albedo, that is the Shortwave surface
reflectance in the range of 0.3-3 micro-meters.  It takes as input
individual bands of surface reflectance originating from MODIS, AVHRR, Landsat
or Aster satellite sensors and calculates the albedo for those.  This is
a precursor to <em>r.sun</em> and any energy-balance processing.

<h2>NOTES</h2>

It uses for Landsat 8 the weighted average reflectance (temporary solution
until an algorithm is found).
<p>
It assumes MODIS product surface reflectance in [0;10000].

<h2>EXAMPLE</h2>
The following example creates the raster map "albedo_lsat7_1987" from the 
LANDSAT-TM5 bands in the North Carolina dataset:
<div class="code"><pre>
g.region raster=lsat5_1987_10 -p
i.albedo -l input=lsat5_1987_10,lsat5_1987_20,lsat5_1987_30,lsat5_1987_40,lsat5_1987_50,lsat5_1987_70 output=albedo_lsat7_1987
</pre></div>
<p>
<center>
<img src="i_albedo_landsat5.png" alt="i.albedo LANDSAT-TM5 1987 example"><br>
<i>Figure: Resulting albedo map from LANDSAT 5</i>
</center>
<p>
The following example creates the raster map "albedo_lsat7_2000" from the 
LANDSAT-TM7 bands in the North Carolina dataset:
<div class="code"><pre>
g.region raster=lsat7_2000_10 -p
i.albedo -l input=lsat7_2000_10,lsat7_2000_20,lsat7_2000_30,lsat7_2000_40,lsat7_2000_50,lsat7_2000_70 output=albedo_lsat7_2000
</pre></div>
<p>
<center>
<img src="i_albedo_landsat7.png" alt="i.albedo LANDSAT-TM7 2000 example"><br>
<i>Figure: Resulting albedo map from LANDSAT 7</i>
</center>

<h2>TODO</h2>

Maybe change input requirement of MODIS to [0.0-1.0]?

<h2>SEE ALSO</h2>

<em>
<a href="r.sun.html">r.sun</a>,
<a href="i.vi.html">i.vi</a>
</em>

<h2>References</h2>
For a 2 band determination of the Aster BB Albedo see the following:
<p>
Salleh and Chan, 2014. Land Surface Albedo Determination: Remote Sensing
and Statistical Validation. in proceedings of FIG 2014
(<a href="https://www.fig.net/resources/proceedings/fig_proceedings/fig2014/papers/ts05g/TS05G_salleh_chan_6910.pdf">PDF</a>)

<h2>AUTHOR</h2>

Yann Chemin

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